Although Casablanca is technically a Romantic Drama, it does lean heavily into Film Noir territory. Because of that and the fact that it is the greatest movie ever produced, I second you opinion:
Casablanca
r
Movies post world war 2 would be considered in the Film Noir genre. Casablanca was during the war, and although B/W and featuring a hard boiled character with a sentimental side—it does not qualify. There is the one where Humphrey plays an escaped convict in the Bridgeport, Lone PIne area of the Eastern Sierra Nevada, I think that would qualify...
I found that movie to be profoundly boring.